Ok now that i've gotten over the shock....
I'm still in disbelief...

I'd like another opinion at the suggestion of NCSrambler that the holes i've found on the flywheel side of the crankcase are not part of the original construction. The picture "Are these holes intentional!" at this location Check out 'Are these holes intentional", are of the cavity just behind the stator plate underneath the flywheel. This '96 Trailblazer engine has been previously removed from the frame to have the cylinder rebored and to remove the gearcase. The crankcase halves were not been seperated, but the inside of case and connecting rod looked clean and i never found any signs of metal pieces when it was upside down. On top of that i can't imagine how the holes were made anyway. I'm not that understanding of the internal structure of this two stroke , but from the dialoge in the other folder 'Hard Starting Trailblazer', it was mentioned by others that it could be a proplem. The two holes esp the one on the bottom are hard to see straight on but they feel ... esp the one on the bottom, like they were intentional. It feels rectangular. Anyway I can't move the bike so i cant take it to anyone for a professionals opinion... so i'm sending this pic out so that someone that is familiar with this side of the crankcase could tell me if these holes belong there.

Thanx

 

I have a 99 tb. It has the same holes. Mine is apart for new crank bearings.
I don't know what the holes are for either but they are factory made!

 

Thank You Talonhawk. Had me really worried there for a minute. Didn't look right to me, but now I know. Thanks again and sorry for the confusion asdfasdfasdfqwer.

 

WHHEWWWWWW!!!!!!

thanks talon...


I was about this close to pulling the enigine and slipping the cylinder off and spliting the casessss....
wow!!!!
I'm still coming down from that rush...
The case looked fine when i had the clyinder off and the thing set on the shop table... and i had upside down
and allll... but then on the other side of the coin... the hole on the right side almost looked like IT COULD
have been punched in there.... Jeeezzzzz.. and then i thought NCScrambler may right... and THAT WAS WHAT
CAUSED THE THING IN THE FIRST PLACE TO SHUT DOWN....
Soooooooooo
I'm back at the beginning and i'd like to ask NC about the airleakage thing again...
Heres's my last post on that topic before we got off on the validity of the holes.....


First lets deal with the engine. Within that you have 1. the combustion chamber, above the pistion and 2. the mixing below it in the crank. Now the only air leak for the combustion is the head, plug and rings which gives us the psi reading. But below it, where all the air, oil and fuel mix i get a little confused. Immediately behind the flywheel and stator plate on my engine i have two holes that look like (and physically would have to.. although i havent split the crankcase into the shaft and connection rod chamber) they go into the connection rod chamber. . theres are these holes on the bottom underneath the bottom coil and another hole just to the lower right of the rightmost coil. these both seem to go to inside the crank... - because when i first started it and discovered i was flooding it alot, i pulled the recoil cover off and the excess oil run out. Anyway, back to the hole in the crankcase wall underneath the stator - from there it's an open air passageway to the outside thru the recoil and out the small water run-off on the bottom of the recoil cover. The one hole on the bottom was designed for flooding i believe and theres even a drain plug there to remove the contents. In any event that means the air is cirulculateing here... So whats up with all this air leaking stuff... i mean thru one of these holes, i can go thru the case to the base of the cylinder RIGHT? So who cares about the seal between the cylinder and the base..? The fact that its a new gasket and it's torqued to specs should be enough. So this air leaking thing confuses me a bit....


thanx
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BTW.... to scramblazer400

i'm still interrested in what your discoveries are...
the last i remember was that you were pulling the carb again and changing the jet?
i'm just going to pull the carb now and check the choke and start
making sure that i'm at the baseline with the settings on this carb
before i start it again

 

to talon...

any possibility you could shot some pics of what the inside of the crankcase halves look like?

thanx

 

No air from outside will not circulate in there. There should be no holes to the outside air underneath the piston anywhere. The holes from the case behind the stator would half to be sealed up when the recoil assy is installed or the case half. There can be air above the piston that will mess up the mixture going into the combustion chamber in many places. The airbox, the carb boot to intake, the head. Now if there are any leaks in those places, you are getting extra air that your jets are not compensating for. Air leaks below the cylinder could be in the base gasket, crankcase halves, oil seals, any openings below the piston to the outside air, will lock an engine up. All of the mixture will be burnt up above the piston (well most) there are small holes in the piston that lets some of the mixture below to help lubricate things beneath. But, most of that would get burnt up over time. If you are running way rich, yes you will have alot of oil/gas laying in the bottom of the crankcase. Here is a link to how the 2 stroke engine works with graphics as it is easy to see than to explain. Hope this helps you understand the problem with airleaks. Oh yeh, Bubba is the one who gave the advise on the cylinder base gasket being blown out. He had problems with his 400 and that was the cause, and he stated to me that the Polaris gasket is much better than aftermarket. 2 Stroke Engines

 

Well I can tell you that the holes do not go into the crankcase. The motor would absolutely not run with holes that big. Primary compression is as much important as the compression above the piston. Without it you would not move any pre-compressed mixture to the top of the piston through the transfers. Just because a base gasket is there doesnt mean a thing. For instance if a small piece of gasket was left on either side it could suck some air. That and the crankcase halves are of the utmost importance when cleaning. They need to be PERFECT. Also the torque needs to be done in a couple of steps and then rechecked after running and cooling down. The 250's are not quite as much of a problem as the 400's, but it can happen too. Being a 96 model the oil you are seeing is primary compressed mixture seeping out around the seals. 2-cycles need the seals redone every few years to be of the most efficient running.Bubba

 

asdfasdasdfqwer,

check your private message!